Exam 9: Antimalarial Drugs

Question 1

What is the most effective way to combat malaria?

Answer 1

Prevention

Killing the mosquitos

Question 2

What is the difference between a clinical cure and a radical cure?

Answer 2

Clinical cure- erythrocytic forms of the parasite are eradicated and the patient has no symptoms.
Radical Cure- All forms of the parasite have been eradicated

Question 3

What is the difference between Causal Prophylaxis and Suppressive Agents?

Answer 3

Causal prophylaxis targets the primary (hepatic) form of the parasite (less practical)
Suppressive Agents- Target erythrocytic forms and suppress symptoms

Question 4

What forms do Chloroquine and Hydroxychloroquine act on?

Answer 4

Erythrocytic forms

Question 5

Chloroquine and Hydroxychloroquine mechanism

Answer 5

Affect the pH of the parasite’s food vacuoles, interfering with their feeding

Question 6

For what species are Chloroquine and Hydroxychloroquine clinical cures? Radical cures?

Answer 6

Clinical cures for all

Radical cures for P. falciparum and P. malariae (not vivax and ovale)

Question 7

What is a problem with the use of Chloroquine and Hydroxychloroquine?

Answer 7

Resistance, especially with P. falciparum

Question 8

What causes resistance to Chloroquine and Hydroxychloroquine?

Answer 8

A transport pump that removes the drug from the parasite

Question 9

How are Chloroquine and Hydroxychloroquine metabolized?

Answer 9

Liver

Question 10

What are adverse effects of Chloroquine and Hydroxychloroquine?

Answer 10

CNS- dizziness, headache, tinnitus
GI Upset
Retina and corneal toxicity
Immunological problems

Question 11

In whom are Chloroquine and Hydroxychloroquine contraindicated?

Answer 11

Patients with psoriasis or porphyria

Due to immune effects

Question 12

What is a special use of Hydroxychloroquine?

Answer 12

Rheumatoid Arthritis and SLE due to its anti-inflammatory actions at high doses
(potential for serious toxicity at these doses though…)

Question 13

What is the mechanism of Quinine and Quinidine?

Answer 13

Interference with digestion of hemoglobin

Question 14

What is a time when you’d use Quinine or Quinidine?

Answer 14

Chloroquine-resistant P. falciparum

Question 15

How are Quinine and Quinidine taken?

Answer 15

Orally.

Also an IV preparation of Quinidine in the US

Question 16

What are adverse effects of Quinine and Quinidine?

Answer 16

GI irritation
Visual and auditory disturbances
Bradycardia
Teratogenic/abortion
Skeletal muscle relaxation
Cinchonism (headache, nausea, vomiting, dizziness, tinnitus, blurred vision)

Question 17

When might you use Mefloquine?

Answer 17

Chloroquine-resistant P. falciparum

Question 18

When shouldn’t you use Mefloquine?

Answer 18

Serious, life threatening infections.

It can only be taken orally.

Question 19

Adverse effects of Mefloquine?

Answer 19

Seizures
Activates latent psychosis
GI and cardiac problems

Question 20

When is Mefloquine contraindicated?

Answer 20

Patients with epilepsy, mental illness, or cardiovascular problems

Question 21

What are two inhibitors of folic acid synthesis that are used to treat Malaria?

Answer 21

Pyrimethamine and Proguanil

Question 22

What is the mechanism of Pyrimethamine and Proguanil?

Answer 22

Inhibition of DHFR

Question 23

When are Pyrimethamine and Proguanil mostly used?

Answer 23

Prophylaxis, especially against Chloroquine-resistant P. falciparum

Question 24

When might you use pyrimethamine plus sulfadoxine combination?

Answer 24

Presumptive treatment (person shows symptoms, but you haven’t diagnosed them for sure yet)

Question 25

What is the mechanism of Atovaquone?

Answer 25

Depolarizes the parasite's mitochondria and inhibiting electron transport

Question 26

What is often used in combo with Atovaquone?

Answer 26

Proguanil (DHFR inhibitor)

Question 27

When might you use Atovaquine + Proguanil?

Answer 27

Prophylaxis against Chloroquine-resistant P. falciparum

Question 28

What are two downsides to Atovaquine + Proguanil?

Answer 28

1. Expensive | 2. Must be taken daily

Question 29

What is artemisinin?

Answer 29

An isolate of an herbal preparation that is part of Coartem.

Question 30

What is Coartem?

Answer 30

A product that contains an artemisinin derivative and is quickly becoming the primary drug used to treat most forms of malaria including Chloroquine-resistant P. falciparum

Question 31

What are a couple of regular antibiotics that have activity against plasmodium species?

Answer 31

Tetracycline//doxycycline

Question 32

What is Primaquine used for?

Answer 32

Follow up treatment when you think a person may have been infected with P. vivax or ovale

Question 33

What is the advantage of Primaquine? Disadvantage?

Answer 33

Can kill the plasmodium parasites in the liver (eradicate latent phase) Disadvantage is that it has toxicities (CNS, GI, and can cause hemolytic anemia in patients with G6PD deficiency)

Question 34

Primaquine toxicity

Answer 34

Hemolytic anemia in patients with G6PD deficiency GI upset Headaches/dizziness

Question 35

What would you use for an acute, uncomplicated attack of malaria?

Answer 35

``` Chloroquine Quinine/Quinidine Coartem (artemether/lumefantrine) Mefloquine Atovaquine + Proguanil Doxycycline ```

Question 36

What is used for a radical cure of P. vivax/ovale?

Answer 36

Primaquine

Question 37

What are 5 drugs used for malaria prophylaxis?

Answer 37

Chloroquine (mostly) Mefloquine (Chloroquine-resistant P. falciparum) Doxycycline Atovaquine + Proguanil Primaquine (follow up therapy to eradicate P. vivix/ovale